JSFiddle - React, Tailwind, and code Playground

HTML

<input id="startdate" />

JavaScript

var fullDate = new Date();

var twoDigitMonth = ((fullDate.getMonth().length+1) === 1)? (fullDate.getMonth()+1) : '0' + (fullDate.getMonth()+1);

$('#startdate').datepicker({
    maxDate: fullDate.getDate() + "/" + twoDigitMonth + "/" + fullDate.getFullYear(),
    beforeShowDay: disableSpecificWeekDays
});


function disableSpecificWeekDays(date) {
    if(date.getDay()==0){
        return [true];
    }else{
        return [false];
    }
}